Moving target-oriented LiFi communication system two-dimensional beam scanning and lighting source integrated design method

Abstract

The invention relates to the technical field of optical communication, and provides a moving target-oriented LiFi communication system two-dimensional beam scanning and lighting source integrated design method, which comprises the following steps: S1, generating initial information; s2, digital signal processing is carried out; s3, carrying out digital-to-analog conversion; s4, converting the electric signal into an infrared light signal; s5, amplifying the signal by an amplifier and outputting the signal from an optical fiber; s6, transmitting the signal to the AWGR; s7, connecting the AWGR to the two-dimensional optical fiber array through an optical fiber; s8, carrying out model selection, driving and modulation on the LED; s9, the LED and the insertion core are interwoven in the two-dimensional optical fiber array; s10, performing energy management; s11, arranging a lens to increase the size of an image surface light spot; s12, transmitting the optical signal to a corresponding receiver; s13, converging and coupling; s14, amplifying the signal by using an amplifier; s15, photoelectric conversion and amplification are carried out through PIN-TIA; s16, performing analog-to-digital conversion on the signal; and S17, restoring the initial information. According to the invention, wavelength control with high capacity and high precision can be provided.

Description

Technical Field

[0001] The present invention relates to the field of optical communication technology, and in particular to a method for integrating two-dimensional beam scanning and illumination light source design of a LiFi communication system for a mobile target. Background Art

[0002] In the future, in areas such as life and production, communication infrastructure must be relied upon for support. Such infrastructure requires not only a powerful and versatile wired network as the backbone of the infrastructure, but also wireless communication links to connect to actual devices. These wireless links need to have the characteristics of high speed, high reliability and low latency. So far, radio frequency signals are most commonly used for wireless communication. However, with the increase in communication speed requirements and the increase in spatial density of connections, the delay requirements for device-to-device interaction are becoming more and more stringent, and radio frequency spectrum resources are gradually in short supply and more likely to cause communication congestion. Wireless optical communication (OWC) technology meets the needs of people's future life and production very well, and is generally considered to be one of the potential key technologies for future communications.

[0003] In order to avoid capacity sharing between devices and thus avoid congestion problems, relatively narrow beams can be used. Narrow beams have a smaller divergence angle, allowing each beam to serve only a single user device. By bringing the optical signal to the corresponding receiver only when needed, the scheme can be more power-efficient and provide better privacy protection. In addition, considering factors such as high energy efficiency and safety, the infrared band is considered to be the most suitable band for beam scanning. By using an infrared beam with a wavelength of 1500nm, the eye safety standard allows the transmission power to be up to 10dBm, which is at least 15dBm higher than the allowed power of visible light beams. In addition, the light intensity brought by the restricted narrow infrared beam on a single user device is higher than that of the more divergent VLC beam. Therefore, narrow infrared optical communication can provide a much higher link power budget than visible light communication, thereby enabling the transmission of higher data rates.

[0004] Moreover, by operating in the S+L+C band (1460-1625nm, equivalent to 20.9THZ bandwidth), the mature fiber-optic communication market provides a wide range of optical equipment options for infrared light beam scanning. Currently widely used beam scanning includes systems with actively controlled beam steering elements (active elements) and systems such as diffraction elements (passive elements). Active element systems such as micro-electromechanical systems (MEMS) or spatial light modulators (SLM-S). Each beam can carry 10Gbit / S or more, but requires a separate steering element. Since the relationship between data signals and control signals needs to be carefully maintained, this limits the ability of the system to expand to more beams and complicates the management and control of the system. Diffraction elements can change the direction of the beam by changing the wavelength of the data signal. The steering of the beam is implicitly controlled by the wavelength, which also carries the data signal, so the wavelength acts as an embedded control channel. This embedding can simplify the management and control of the system. Common diffraction elements include a pair of reflection or transmission gratings, a glass body containing many Bragg grating structures, etc. for two-dimensional steering.

[0005] Although active electronically controlled devices can provide higher wave scanning accuracy and dynamic control, they are complex to manufacture and have increased power consumption. Compared with passive devices, active devices require longer response time, that is, the delay is too large. Traditional passive devices have limited scanning angles and their accuracy needs to be improved. Summary of the invention

[0006] The present invention provides a method for integrating two-dimensional beam scanning and illumination light source design of a LiFi communication system for mobile targets, which can provide high-capacity and high-precision wavelength control.

[0007] According to the present invention, a method for integrating two-dimensional beam scanning and illumination light source design of a LiFi communication system for a mobile target includes the following steps:

[0008] S1 generates the initial data information flow;

[0009] S2 performs digital signal processing DSP on the data information;

[0010] S3 converts the digital signal processed data into an electrical signal through a digital-to-analog converter DAC;

[0011] S4 feeds the electrical signal to a single-drive Mach-Zehnder modulator, and uses the analog electrical signal output and the optical signal generated by the laser LD as the input of the modulator, modulating the digitally processed signal into an infrared optical signal;

[0012] S5 uses erbium-doped fiber amplifier (EDFA) to amplify infrared light signals, and the signals are output through single-mode optical fiber;

[0013] S6 transmits the infrared signal to the arrayed waveguide grating router AWGR through a single-mode optical fiber;

[0014] The S7AWGR is connected to the two-dimensional optical fiber array end-to-end using single-mode optical fiber, and the infrared light signal is emitted from the optical fiber ferrule on the optical fiber array to perform spatial optical transmission;

[0015] S8 selects, drives and modulates the light-emitting diode LED according to the transmission distance;

[0016] S9 interweaves LEDs and single-mode fiber ferrules in a two-dimensional fiber array to synchronously control LED illumination and beam scanning;

[0017] S10 performs energy management on LED light sources;

[0018] S11 sets a lens coaxial with the fiber array in the optical path to increase the image spot size and realize wavelength-tuned two-dimensional beam scanning;

[0019] The S12 optical signal is transmitted through free space to the receiver at the corresponding position;

[0020] The S13 optical signal is collected by the collimator at the receiving end and coupled into the single-mode optical fiber;

[0021] S14 uses a linear semiconductor optical amplifier to amplify the received signal and increase the received power;

[0022] S15 uses a diode-transimpedance amplifier PIN-TIA to perform photoelectric conversion on the amplified optical signal and further amplify the converted electrical signal;

[0023] S16 uses an analog-to-digital converter ADC to perform analog-to-digital conversion on the electrical signal and collect the converted digital signal;

[0024] S17 performs digital signal processing on the collected digital signal to restore the original information.

[0025] Preferably, in S4, a modulator is used to carry the signal in an infrared band with a wavelength of λ.

[0026] Preferably, in S6, the AWGR has multiple output ports, and infrared light signals of different bands are output from different ports respectively.

[0027] Preferably, in S7, the mode field radius of the single-mode optical fiber is w0, and the applicable wavelength is λ, so the light wave divergence angle α is described as:

[0028]

[0029] One end of the single-mode optical fiber is connected to the AWGR using FC or APC, and the other end is connected to the optical fiber array using a ferrule. The optical fiber array is honeycomb-shaped, and the fiber gap between adjacent optical fibers is Δy.

[0030] Preferably, in S7, LEDs and optical fiber ferrules are arranged in a two-dimensional array using an interlaced arrangement method to ensure uniform illumination and scanning of the image plane.

[0031] Preferably, in S8, the LED power is adjusted by the driving circuit so that the LED output light intensity matches the ambient light intensity to ensure uniform illumination in the communication environment; the LED can be modulated into a communication signal to enhance the function of visible light communication VLC; and the radius r of the LED spot should satisfy:

[0032] 2r≥L

[0033] Where L is the width of the receiving end image plane. For the illumination divergence angle β, it must satisfy:

[0034]

[0035] Where b0 is the distance from the transmitter to the receiver.

[0036] Preferably, in S9, the LED and the AWGR can be arranged in a variety of spatial topologies, and the LED illumination light and the AWGR infrared beam scanning can be coordinated through a synchronous control circuit.

[0037] Preferably, in S10, during the lighting process, the LED is monitored and adjusted in real time through the intelligent energy management system, that is, the working state of the LED is automatically optimized according to the ambient light conditions and application requirements; the working mode of the LED is dynamically adjusted according to the communication load and lighting requirements.

[0038] Preferably, in S10, the lens uses a defocusing method to further reduce the required hardware and space size, that is, to reduce the distance v from the two-dimensional optical fiber array to the lens. The relative defocus parameter p is described as:

[0039] p=1-v / f

[0040] The focal length of the lens, f, is described as:

[0041]

[0042] Where M is the number of ports on the diagonal line of the fiber array. In order to ensure that the light spot at the receiving end at a distance of lens b0 is covered without gaps, that is, the light spot is external, the fiber gap on the fiber array should meet the following requirements:

[0043]

[0044] In addition, to ensure that the light waves of each port pass through the lens perfectly, the diameter of the front lens group is Dlens Should meet:

[0045] Dlens≥(M-1)|Δy|+2f(1-p)tanα.

[0046] As a preferred embodiment, in S10, signals from transmitters of different wavelength bands are received by receivers at different positions; the diameter D of the lens of the front lens group of the collimator at the receiving end is lens Need to meet:

[0047] D lens =2tanα{f+p(bf)}

[0048] Where b is the distance between the transmitting and receiving lenses.

[0049] The beneficial effects of the present invention are as follows:

[0050] 1. High-precision beam scanning. It can accurately transmit each wavelength signal to the corresponding receiver.

[0051] 2. Fast response time. It can quickly scan the required receiving end location and transmit information.

[0052] 3. Accurate wavelength control. Different wavelength signals are output through different ports, which makes the control of signal wavelength very precise.

[0053] 4. Simple system management and control. No separate steering components are required, and the relationship between data signals and control signals is simple to maintain.

[0054] Compared with other passive component systems, the present invention uses more precise wavelength control to achieve higher-precision scanning and greatly increases user capacity. At the same time, as a passive device, AWGR does not produce a large delay and is more capable of facing moving targets. In addition, the present invention integrates the AWGR wave scanning system with the illumination light source, solving the shortcoming that the narrow beam system cannot provide illumination. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a flow chart of a method for designing an integrated two-dimensional beam scanning and lighting source of a LiFi communication system for a mobile target in an embodiment;

[0056] Figure 2 An experimental diagram of a method for integrating two-dimensional beam scanning and illumination light source design of a LiFi communication system for a mobile target in an embodiment;

[0057] FIG3( a ) is a design diagram of a two-dimensional optical fiber array of a spatial topology solution in which LEDs and AWGRs are arranged in an interlaced manner in an embodiment;

[0058] FIG3( b ) is a two-dimensional optical fiber array design diagram of a spatial topology solution in which LEDs and AWGRs are arranged in an equilateral triangle at the center of the optical fiber array in an embodiment;

[0059] Figure 4 Schematic diagram of the defocusing method in the embodiment. DETAILED DESCRIPTION

[0060] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the embodiments are only for explaining the present invention and are not intended to limit it.

[0061] Example

[0062] like Figure 1 and Figure 2 As shown, this embodiment provides a method for integrating two-dimensional beam scanning and lighting source design of a LiFi communication system for a mobile target, which includes the following steps:

[0063] S1 generates the initial data information flow;

[0064] S2 performs digital signal processing DSP on the data information;

[0065] S3 converts the digital signal processed data into an electrical signal through a digital-to-analog converter DAC;

[0066] S4 feeds the electrical signal to a single-drive Mach-Zehnder modulator, and uses the analog electrical signal output and the optical signal generated by the laser LD as the input of the modulator, modulating the digitally processed signal into an infrared optical signal;

[0067] S5 uses erbium-doped fiber amplifier (EDFA) to amplify infrared light signals, and the signals are output through single-mode optical fiber;

[0068] S6 transmits the infrared signal to the arrayed waveguide grating router AWGR through a single-mode optical fiber;

[0069] The S7 AWGR and the two-dimensional fiber array are connected end-to-end using single-mode optical fibers, and the infrared light signal is emitted from the fiber ferrule on the fiber array for spatial optical transmission;

[0070] S8 selects, drives and modulates the light-emitting diode LED according to the transmission distance;

[0071] S9 interweaves LEDs and single-mode fiber ferrules in a two-dimensional fiber array to synchronously control LED illumination and beam scanning;

[0072] S10 performs energy management on LED light sources;

[0073] S11 sets a lens coaxial with the fiber array in the optical path to increase the image spot size and realize wavelength-tuned two-dimensional beam scanning;

[0074] The S12 optical signal is transmitted through free space to the receiver at the corresponding position;

[0075] The S13 optical signal is collected by the collimator at the receiving end and coupled into the single-mode optical fiber;

[0076] S14 uses a linear semiconductor optical amplifier to amplify the received signal and increase the received power;

[0077] S15 uses a diode-transimpedance amplifier PIN-TIA to perform photoelectric conversion on the amplified optical signal and further amplify the converted electrical signal;

[0078] S16 uses an analog-to-digital converter ADC to perform analog-to-digital conversion on the electrical signal and collect the converted digital signal;

[0079] S17 performs digital signal processing on the collected digital signal to restore the original information.

[0080] In S4, a modulator is used to carry the signal in the infrared band with a wavelength of λ.

[0081] In S6, the AWGR has multiple output ports, and infrared light signals of different wavelengths are output from different ports. In this embodiment, a 96-port AWGR can be selected to output 96 infrared lights of 1500nm to 1600nm wavelengths.

[0082] In S7, the mode field radius of the single-mode fiber is w0, and the applicable wavelength is λ, so the light wave divergence angle α is described as:

[0083]

[0084] One end of the single-mode optical fiber is connected to the AWGR using FC or APC, and the other end is connected to the optical fiber array using a ferrule. The optical fiber array is honeycomb-shaped, the array is more compact, and the optical fiber gap between adjacent optical fibers is Δy.

[0085] In S7, LEDs and fiber optic ferrules are arranged in a two-dimensional array using an interlaced arrangement method to ensure uniform illumination and scanning of the image plane.

[0086] In this embodiment, each port of the AWGR corresponds to each port of the fiber array, and is connected using a single-mode fiber. One end of the fiber is connected to the AWGR using FC / APC, and the other end is connected to the fiber array using a ferrule. The fiber array is designed to be honeycomb to make the array more compact. In order to minimize the lens size, the fiber gap is selected to be 1.4mm, and the mode field diameter of the single-mode fiber is selected to be 10.5μm.

[0087] In S8, the LED power is adjusted by the driving circuit so that the LED output light intensity matches the ambient light intensity to ensure uniform illumination in the communication environment; the LED can be modulated into a communication signal to enhance the function of visible light communication VLC; for the radius r of the LED spot, it should satisfy:

[0088] 2r≥L

[0089] Where L is the width of the receiving end image plane. For the illumination divergence angle β, it must satisfy:

[0090]

[0091] Where b0 is the distance from the transmitter to the receiver.

[0092] In S9, LED and AWGR can be arranged in various spatial topologies, such as interlaced arrangement of LED and optical fiber, as shown in Figure 3(a), and arrangement of LED in an equilateral triangle with the center of the optical fiber array, as shown in Figure 3(b). Through the synchronous control circuit, the illumination light of the LED and the infrared beam scanning of the AWGR are coordinated. This step ensures that the uniformity and brightness of the spatial illumination are not affected while the optical signal is transmitted.

[0093] In S10, during the lighting process, the LED is monitored and adjusted in real time through the intelligent energy management system, that is, the working state of the LED is automatically optimized according to the ambient light conditions and application requirements (brightness, color temperature), so that the LED can achieve higher functionality and lower energy consumption; according to the different communication loads and lighting requirements, the working mode of the LED is dynamically adjusted to reduce unnecessary energy waste.

[0094] In order to further reduce aberrations (especially field curvature), a commercial lens with a focal length of f 50mm and an aperture of f 0.95 was selected in S10. The diameter of the rear lens group is only 24mm, which meets the requirements of S7 for the light emitted by the fiber array to pass through the lens perfectly. Figure 4 As shown, the lens uses a defocusing method to further reduce the required hardware and space size, that is, to reduce the distance v from the two-dimensional fiber array to the lens. The relative defocus parameter p is described as:

[0095] p=1-v / f

[0096] The focal length of the lens, f, is described as:

[0097]

[0098] Where M is the number of ports on the diagonal line of the fiber array. In order to ensure that the light spot at the receiving end at a distance of lens b0 is covered without gaps, that is, the light spot is external, the fiber gap on the fiber array should meet the following requirements:

[0099]

[0100] In addition, to ensure that the light waves of each port pass through the lens perfectly, the diameter of the front lens group is D lens Should meet:

[0101] Dlens≥(M-1)|Δy|+2f(1-p)tanα.

[0102] In S10, signals from transmitters of different bands are received by receivers at different positions; the diameter of the lens of the collimator in front of the receiver is D lens Need to meet:

[0103] D lens =2tanα{f+p(bf)}

[0104] Where b is the distance between the transmitting and receiving lenses.

[0105] This embodiment uses precise wavelength control to achieve higher-precision scanning and greatly increases user capacity. At the same time, as a passive device, AWGR does not produce large delays and is more capable of targeting moving targets. In addition, this embodiment integrates the AWGR scanning system with the illumination light source, solving the shortcoming that the narrow beam system cannot provide illumination.

[0106] The present invention and its embodiments are described schematically above, and the description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and designs a structural method and an embodiment similar to the technical solution without creativity without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. A method for integrating two-dimensional beam scanning and lighting source design of a LiFi communication system for mobile targets, characterized in that: The following steps are involved: S1 generates the initial data information flow; S2 performs digital signal processing DSP on the data information; S3 converts the digital signal processed data into an electrical signal through a digital-to-analog converter DAC; S4 feeds the electrical signal to a single-drive Mach-Zehnder modulator, and uses the analog electrical signal output and the optical signal generated by the laser LD as the input of the modulator, modulating the digitally processed signal into an infrared optical signal; S5 uses erbium-doped fiber amplifier EDFA to amplify infrared light signals, and the signals are output through single-mode optical fiber; S6 transmits the infrared signal to the arrayed waveguide grating router AWGR through a single-mode optical fiber; The S7 AWGR and the two-dimensional fiber array are connected end-to-end using single-mode optical fibers, and the infrared light signal is emitted from the fiber ferrule on the fiber array for spatial optical transmission; S8 selects, drives and modulates the light-emitting diode LED according to the transmission distance; S9 interweaves LEDs and single-mode fiber ferrules in a two-dimensional fiber array to synchronously control LED illumination and beam scanning; S10 performs energy management on LED light sources; S11 sets a lens coaxial with the fiber array in the optical path to increase the image spot size and realize wavelength-tuned two-dimensional beam scanning; The S12 optical signal is transmitted through free space to the receiver at the corresponding position; The S13 optical signal is collected by the collimator at the receiving end and coupled into the single-mode optical fiber; S14 uses a linear semiconductor optical amplifier to amplify the received signal and increase the received power; S15 uses a diode-transimpedance amplifier PIN-TIA to perform photoelectric conversion on the amplified optical signal and further amplify the converted electrical signal; S16 uses an analog-to-digital converter ADC to perform analog-to-digital conversion on the electrical signal and collect the converted digital signal; S17 performs digital signal processing on the collected digital signal to restore the original information.

2. The method for designing an integrated two-dimensional beam scanning and lighting source for a mobile target LiFi communication system according to claim 1, characterized in that: In S4, a modulator is used to carry the signal in the infrared band with a wavelength of λ.

3. The method for designing an integrated two-dimensional beam scanning and lighting source for a LiFi communication system for a mobile target according to claim 2, characterized in that: In S6, AWGR has multiple output ports, and infrared light signals of different bands are output from different ports.

4. The method for designing an integrated two-dimensional beam scanning and lighting source for a LiFi communication system for a mobile target according to claim 3, characterized in that: In S7, the mode field radius of the single-mode optical fiber is w0, and the applicable wavelength is λ, so the light wave divergence angle α is described as: One end of the single-mode optical fiber is connected to the AWGR using FC or APC, and the other end is connected to the optical fiber array using a ferrule. The optical fiber array is honeycomb-shaped, and the fiber gap between adjacent optical fibers is Δy.

5. The method for designing an integrated two-dimensional beam scanning and lighting source for a LiFi communication system for a mobile target according to claim 4, characterized in that: In S7, LEDs and fiber optic ferrules are arranged in a two-dimensional array using an interlaced arrangement method to ensure uniform illumination and scanning of the image plane.

6. The method for designing an integrated two-dimensional beam scanning and lighting source for a mobile target LiFi communication system according to claim 5, characterized in that: In S8, the LED power is adjusted by the driving circuit so that the LED output light intensity matches the ambient light intensity to ensure uniform illumination in the communication environment; the LED can be modulated into a communication signal to enhance the function of visible light communication VLC; for the radius r of the LED spot, it should satisfy: 2r≥L Where L is the width of the receiving end image plane. For the illumination divergence angle β, it must satisfy: Where b0 is the distance from the transmitter to the receiver.

7. The method for designing an integrated two-dimensional beam scanning and lighting source for a LiFi communication system for a mobile target according to claim 6, characterized in that: In S9, LED and AWGR can be used in a variety of spatial topologies, and the LED lighting and AWGR infrared beam scanning can be coordinated through the synchronous control circuit.

8. The method for designing an integrated two-dimensional beam scanning and lighting source for a mobile target LiFi communication system according to claim 7, characterized in that: In S10, during the lighting process, the LED is monitored and adjusted in real time through the intelligent energy management system, that is, the working state of the LED is automatically optimized according to the ambient light conditions and application requirements; the working mode of the LED is dynamically adjusted according to the communication load and lighting requirements.

9. The method for designing an integrated two-dimensional beam scanning and lighting source for a LiFi communication system for a mobile target according to claim 8, characterized in that: In S10, the lens uses a defocusing method to further reduce the required hardware and space size, that is, to reduce the distance v from the two-dimensional fiber array to the lens. The relative defocus parameter p is described as: p=1-v / f The focal length of the lens, f, is described as: Where M is the number of ports on the diagonal line of the fiber array. In order to ensure that the light spot at the receiving end at a distance of lens b0 is covered without gaps, that is, the light spot is external, the fiber gap on the fiber array should meet the following requirements: In addition, to ensure that the light waves of each port pass through the lens perfectly, the diameter of the front lens group is D lens Should meet: Dlens≥(M-1)|Δy|+2f(1-p)tanα.

10. The method for designing an integrated two-dimensional beam scanning and lighting source for a LiFi communication system for a mobile target according to claim 9, characterized in that: In S10, signals from transmitters of different bands are received by receivers at different positions; the diameter of the lens of the collimator in front of the receiver is D lens Need to meet: D lens =2tanα{f+p(b-f)} Where b is the distance between the transmitting and receiving lenses.

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